feat: external goosed server

[michaelneale]

fixes: https://github.com/block/goose/issues/4115 which has been requested a few times. Let the goose app connect to any goose server.

example motivation:

I work on highly regulated genomics data that sits in a protected environment. Being able to run a desktop on a local computer that is connected via ssh to some sort of 'goose server" running in the protected environment would be helpful. For example, I could loop at data visualizations in the desktop app, which would be impossible via the goose CLI in a terminal.

If you accidentally start it and it can't connect:

you can then run a goose server with:

./target/release/goosed agent

and use the defaults in the form (127.0.0.1, port 3000, secret is 'test')